Many people have to deal with this concept, but not everyone knows what humus is. Translated from Latin, "humus" means "earth", "soil" and is the main organic matter containing nutrients that plants simply need.
Humic substances belong to a special group of chemical compounds characteristic of the earth's soil cover, that is, they are specific only to the soil. Surely, what is humus, now it has become clear, but what is it formed from? From the remains of plants, animals and microbes as a result of interaction with various components of the environment.
The chemical composition of humus is quite complex. It is characterized by a dark color, which is absent in plants. The composition of humus includes a very valuable humic acid containing a lot of carbon (about 60%), oxygen (about 35%), nitrogen (on average 5%), phosphorus, sulfur, iron, and so on. Based on the foregoing, another answer follows to the question of what humus is. Humus is a term that combines a huge complex of chemicals containing in their composition an organic part (humic and fulvic acids), an inorganiccomponent (chemical elements of inorganic origin, or, in other words, minerals, which are among the humates and fulvates). But let's talk about this in more detail now.
How is humus formed?
You have already met the concept of humus, the next open question is what is soil humus, and how is it formed? Soil humus is nothing but a waste product of various organisms, primarily earthworms. The process of humus formation is long-term.
Vegetation, metabolic products, animal remains - all this is food for organisms that live in the soil. Some part of all this lends itself to mineralization, and the other part - to biochemical enzymatic decomposition and oxidation (humification), during which the synthesis of organic compounds occurs, and humus is formed. Humus predominates in it, as well as humic acids, which are converted over time, oxidizing as a result to carbon dioxide and water. It is very important that the ways of humus transformation - mineralization or humification - depend directly on soil and climatic conditions. In fairly warm and humid climates, the oxidation process occurs very quickly, and almost all vegetation litter is mineralized, which prevents humus from accumulating in the soil. In cold climates, the transformation of litter is slightly slower, and their number is small, as a result of which the humus content in the soil is low. Optimal for humification are temperate climates withoutwaterlogging.
So, from the above, we can draw the appropriate conclusions:
- to get a good harvest, the plant simply needs carbon dioxide;
- carbon dioxide in the soil, as a rule, is formed as a result of the decomposition of the remains of plants, animals and microbes when interacting with various components of the environment (microorganisms, insects, worms, fungi, and so on);
- processed organic remains of plants, animals and microbes and form humus, which is the most important component of soil fertility.
Functions of humus
- Physical function. It creates a solid soil structure, which ensures favorable circulation of water, air of the required temperature and predetermines good root growth in the soil. Humus also helps bind light soils and loosen dense soils.
- Chemical function. It is an excellent store of nutrients. As a result of the activity of various microorganisms, humus decomposes over time (the process of mineralization), as a result of which the nitrogen, phosphorus, potassium and other elements contained in it are released.
- Biological function. Humus creates favorable conditions for the development and further activity of various microorganisms.
Types of humus
- Mor (podzolic soil humus). Humus of this type is very coarse,containing a large amount of detritus, formed at low biological activity in an acidic environment.
- Moder (humus of soddy-podzolic soil), formed at medium biological activities under acidic conditions and weakly interacting with the mineral part of soils.
- Müll (chernozem humus), formed at very high biological activities in the condition of a neutral reaction of the environment, actively interacting with the mineral part of the soil.
- Anmoor (humus of soddy-gley soil), which forms in temporarily moist soils.
- Aligotrophic peat, which is the "poor humus" of raised bogs.
- The last type is eutrophic peat, which is the "rich humus" of lowland bogs.
The importance of humus in soil fertility
Humus is actively involved in the process of soil formation. It plays the most important role directly in the formation of the soil profile. Humus contributes to the gluing of soil particles into aggregates (lumps), creates agronomically valuable structures and physical properties of the soil favorable for plant life. It contains essential plant nutrients and various micronutrients available to plants after the mineralization process.
Humic substances are food for soil microorganisms. The intensity of various chemical and biological processes that cause the accumulation of substances necessary for plants depends on the humus content in soils. Humus also contributes to giving the soil a dark color, thusthe earth is better at absorbing solar energy.
Composition and properties of humus
This fertilizer is a complex dynamic complex of organic compounds that are formed during the decomposition of various organic residues.
In the composition of soil humus, one can distinguish a specific part (about 90%), consisting of humic substances, and a non-specific part (the rest), consisting of non-humified organic substances. Soil humic substances, in turn, are represented by:
- humic acids - high-molecular nitrogen-containing organic compounds with a cyclic structure, insoluble in water and acids, but soluble in weak alkalis, humic acids contain carbon (about 50%), hydrogen (5%), oxygen (40%), nitrogen (5%);
- humates formed as a result of the interaction of humic acids with the mineral part of the soil; alkali humates are highly soluble in water, thereby forming colloidal solutions; humates of calcium and magnesium are not soluble in water, form a water-resistant structure;
- fulvic acids - high-molecular nitrogen-containing organic acids, soluble in water, various acids and alkali solutions, in addition, they are able to dissolve in some organic solvents; Fulvic acids contain carbon, hydrogen, oxygen and nitrogen, and I would also like to note that these acids contribute to the active destruction of the mineral part of the soil.
The value of humus for plants
About everyoneThe merits of humic substances are still not known, therefore, below are only the main ones that are firmly rooted in theory and practice.
Thus, humus is a fertilizer that promotes:
- stimulating plant respiration even in acute oxygen deficiency;
- improving the quality of agricultural products;
- enhanced photosynthesis, stimulating the activity of enzymes that are directly related to photosynthetic reactions;
- acceleration of transport and circulation of nutrients directly inside plants;
- plant growth and development;
- activation of root formation and bud development;
- increasing resilience to external adverse impacts;
- formation of strong compounds with metals, absorption of phosphates, nitrates and many others;
- increase in acidity on the root surface;
- increasing the resistance of plants to the effects of pesticides and herbicides, reducing their accumulation in the final product.
The use of humic substances in medicine
According to the results of various pharmacological tests carried out in order to identify what humus is, preparations based on humic substances can be used in our time in medicine and veterinary medicine as a non-specific medicine that helps increase the body's resistance to the effects of various harmful factors.
Medical medicines based on these humic substances are already on sale in our time. They are actively used in the treatment of radiculitis of various forms,diseases of the ears and nose, pharyngitis, rhinitis, arthritis, polyarthritis, arthrosis and many other diseases. The advantage of these drugs is that they are non-toxic.
Mysteries of the humic substance
So the story about what soil humus is, about its formation, properties and functions has come to its logical conclusion. The only thing I would like to add is a few words about the mysteries of humic substances. As you know, they do not have a constant chemical composition, they do not have a certain molecular weight and a constant single color. Humic substances are still being studied by chemists, soil scientists, hydrobiologists, doctors, pharmacists in order to explain all the mysteries stored in them, which, according to forecasts, will be solved a lot more.
